Meanings?

c1400–

kappa, n.

The tenth letter of the Greek alphabet, Κ, κ.

1945–

kappa, n.

Biology. An agent in some strains of Paramecium aurelia that confers on cells possessing it the property of producing a substance toxic to Paramecium…

1799–

Phi Beta Kappa, n.

An intercollegiate society to which distinguished (usually undergraduate) scholars may be elected as an honour. Frequently attributive.

1854–

Phi Beta Kappa, n.

A member of such a society.